In electric power distribution systems, electric cut-outs are used to provide protection to the lines of the distribution system and various apparatus on the line such as transformers, capacitors banks, etc. Frequently in storms and at night, utility linemen and workmen are required to replace or otherwise service high, above-ground distribution fuse cut-out switches.
FIG. 1 discloses, in outline, form an array of typical prior art fuse cut-out switch assemblies. U.S. Pat. No. 4,326,184 is typical; insulator 1 is mounted on a bracket 2 and has a pair of spaced contact assemblies 5 and 8. Contact assembly 14 has a pair of aligned trunnion sockets formed therein, only one being shown. The elongated fuse tube 11 has at one end a trunnion contact end assembly with a pair of laterally extending trunnion members 47 (only are shown) receivable in the pair of trunnion sockets 33 (only one shown) and, at the opposite end of the fuse tube 11, is a second latching contact end 25 adapted to contact and latch with the second of the contact assemblies on insulator 1. A hook stick ring 40 is integrally cast as part of the drop-out hinge assembly and an operating eye 27 is integrally cast with the upper fused contact assembly. In some cases, the upper operating eye 27 automatically lifts a sleet shield and pulled with hook sticks by the lineman to disengage the cut-out switch.
In the case of removing the fuse cut-out switch for servicing or replacement and in lifting or removing the fuse holder by the use of a hook stick, particularly in storms and windy conditions (which typically is the case), the fuse tube and its switch contact assemblies frequently fall off when lifting to engage the trunnion sockets, or are blown off or it is difficult to engage the hook stick with the operating eye 27 or the hook stick ring 40. In wind storms, particularly at 40, 45 and 50 feet above ground, the lineman can have great difficulty in manipulating the hook stick (sometimes called "hot-switch stick") engagement member which projects laterally from the axis of the hook stick. The operating eye 27 and the hook stick ring 40 are made large relatively, so as to enable ease of engagement from the ground. But, even these expediencies are not sufficient to make it easy for the lineman to engage the operating eye properly or the hook stick ring for lifting and/or removing the fuse holder. Frequently they jiggle and are blown off of the end of the hook stick and fall upon the head and shoulders and feet of the trouble person or assistant or other workers, sometimes injuring them. At any rate, at night, it is quite difficult and dangerous to work and can be time consuming.
Attempts to solve this problem have not been particularly well received because of their complexity and difficulty of use. For example, in Manning U.S. Pat. No. 4,480,244 an apparatus is provided for remote closing of fuse circuits in which a pivotally carried fuse tube has a crank extending therefrom that is to be positioned and a cord extending to the ground for swinging the fuse tube to an upward position to close the circuit with the apparatus normally sliding off the fuse tube and in a closed position but, being removable by pulling the cord from the ground. It will be noted in the Manning patent the large size operating eye and the large size hook stick rings.
In Mannen U.S. Pat. No. 2,936,193, a switch stick for manipulating an installation of fuses on overhead lines is disclosed which has a shaft grope operated carrier slidable along the stick for releasably supporting the fuse member with the stick having its upper end to engage a fused mounting.
Hubbard U.S. Pat. No. 3,810,060 uses a lanyard and lever arm to operating the switch. Reference is also made to the following U.S. patents which disclose various shapes and configurations of operating eye and hook switch rings:
Mee et al. U.S. Pat. No. 4,636,764 PA1 Lemmon U.S. Pat. No. 2,172,143 PA1 Bronikowski U.S. Pat. No. 3,374,329 PA1 Schultz U.S. Pat. No. 2,365,113 PA1 Sant U.S. Pat. No. 2,703,349 PA1 Jackson, Jr. U.S. Pat. No. 4,307,369 PA1 Schmunk U.S. Pat. No. 4,313,100 PA1 Birknmeir U.S. Pat. No. 2,235,666 PA1 Billar U.S. Pat. No. 4,414,527 PA1 McNaghten, et al. U.S. Pat. No. Des. 278,331
While the invention is particularly applicable to cut-out type distribution switches, it will be readily apparent to those skilled in the art that the safety features of the invention, in its broader aspects, are applicable to interrupter switches for live-line switch installations as well.
The invention features a high above-ground distribution fuse cut-out switch having a pair of spaced contact assemblies supported and spaced by a ceramic insulator and appropriately carried on a mounting member upon a power pole, say 30-50 feet above ground. One of the spaced contact assemblies has a pair of laterally aligned trunnion sockets formed therein and an elongated fuse assembly having a trunnion contact end with a pair of laterally extending trunnion members receivable in the pair of trunnion sockets. A second latching contact end is adapted to contact and latch the second of the contact assemblies when the fuse assembly is rotated on the trunnions. The invention is directed to means to safely and efficiently facilitate the mounting of the elongated fused assembly to engage the pair of spaced contact assemblies from the ground level by a hot switch stick or hook stick. According to the invention, the trunnion contact end includes an elongated slot having a width W which slot is preferably substantially aligned with the elongated fuse tube. The hot/switch stick has an axis and a stub shaft or member projecting laterally of the hot stick length axis with an enlargement on the end of the projecting member which is larger than the slot width W. It has an intermediate portion of the projecting member which is narrower than the slot width W such that the projecting member easily slides in the slot and the weight of the fuse tube and pairs of contact ends in the slot being of a length such that jiggling and wind forces are insufficient to displace the projection from the slot while the hot/switch stick is being raised to fit the laterally extending trunnion members into the trunnion sockets. The safety slot is aligned with the fuse tubes such that the laterally projecting member on the hook switch or hot switch stick can be rested along the length of the fuse tube and guided along the fuse tube and into the slot to thereby facilitate engagement of the hook stick switch when the trunnion members are in the trunnion sockets for removal of the trunnion members and fuse assembly from the trunnion sockets. Furthermore, an open-sided operating eye member is provided with the open side aligned with the tube so that the projecting member on the hot/switch stick can engage and be easily guided by the tube into engagement with the hook from the ground level. In this way, when a switch is to be removed for servicing and/or replacement, the lineman on the ground can easily press the projecting member or lateral shaft of the hot/switch stick on the fuse tube (anywhere along the length) from the ground and then be guided upwardly and into the hook portion of the operate eye and thereby pull downwardly so as to open the switch (in those switch types that operate in that manner). Then, placing the projecting member of the hot/switch stick on the opposite side of the tube, the lineman can guide the projecting member into the slot and lift the pair of laterally extending trunnion members out of the trunnion sockets down to the ground without the fuse cut-out assembly falling off of the hook switch and hitting the trouble person on the head or shoulders or injuring other workmen, or getting lost in trees, brush, streams, ponds or lakes. The invention can save 1/4 to 1/2 the normal replacement time.
The different manufacturers have not generally made their units compatible with one another's. Accordingly, there are some fuse assemblies which are relatively long and others with are somewhat shorter and some have different latch mechanisms.
Another feature of the present invention provides for rotary and length-wise adjustment of the trunnion contact assembly along the axis of the fuse tube so that the universal fuse holder of the present invention will fit long as well short fuse holders so that the trouble person, if the trouble person has to go out at night, need to have one type of fuse holder to fit many different types of switches instead of having several on the repair truck. This makes it easy to accommodate several different types of cut-out fuse switches. It takes a short period of time to adapt the universal fuse holder--even in a storm it wouldn't be hard to do. In some cases, the lineman needs to take a hacksaw to saw off a short portion of the fuse.
In summary, the invention features a safety device that enables the lineman to raise and lower and operate the fuse in a much safer fashion, particularly in storms so that they do not get hurt during storms and do not loose the fuse holders in bushes and in the trees, rivers and canals when it falls out of the hot/switch pole. In contrast, in a conventional cut-out switch, the lineman must insert the projecting member into a ring of about 11/4 to 11/2 inch diameter and, with the wind blowing it is almost impossible. In the present invention, the tube is used as a guide to slide right into the slot and when the wind is blowing this gives the target of 8 inches to 1 foot for the lineman to rest the projecting member against the fuse tube body (the different distances being due to the different lengths of the fused bodies). Moreover, with prior art systems, the lineman has to aim the projecting member at the end of the hot stick from the side of the hook ring. Being on the ground and viewing from the side edge has a different viewing angle of the hole in the hook ring. And, as noted above, when the wind is blowing and on a 35 to 40 foot pole and viewing the hole from the ground and coming in from the side edge of the hook ring hole which makes it very difficult to install in inclement weather and in the dark. The invention solves these problems in an efficient and safe way.
The safety device attachment of this invention attaches to the fuse cut-out tubular body and is adapted to move and engage the contact assembly and prevent rotation thereof relative to the tubular body to make it easier to remove blown units and reinstall new or refused units.